Examples

Heating oil shale to a sufficiently high temperature will drive off a vapor which processing can distill (retort) to yield a petroleum-like shale oil-a form of non-conventional oil-and combustible shale gas (the term shale gas can also refer to gas occurring naturally in shales).

MUMBAI -- India plans to sign an initial agreement with the U.S. in shale gas exploration, as it prepares to auction blocks by the end of next year to tap the fuel source, top oil ministry officials said Monday.

The South Asian nation's interest in shale gas stems from the fact that the U.S. has attracted heavy investments in the sector from global energy giants such as Royal Dutch Shell and Exxon Mobil as well as Reliance Industries, India's largest company by market value.

The South Asian nation 's interest in shale gas stems from the fact that the U.S. has attracted heavy investments in the sector from global energy giants such as Royal Dutch Shell PLC and Exxon Mobil Corp. as well as Reliance Industries Ltd.,